Layers section is not in the render settings panel?
I assume that you are mixing two different tabs of the Properties editor into one.
The Performance section is in Render tab of the Properties editor (camera icon), see image below:



The Layers and Passes sections (which are needed for compositing) are in the Render Layers tab (small pictures icon, second from left), see image:





Check out this BlendFile. Note that there are two render Layers (A and B). 

Both have scene layers 1, 2 and 10 enabled in Scene layer selection. 

In Render Selection, "RenderLayer-A" has layers 1 and 10 enabled, and 
"RenderLayerB" has layers 2 and 10 enabled.